Generator



E. D. SMlTH Jan. 5 1926.

GENERATOR Filed Oct. 22. 1925 SATU RATE D INVENTOR. I Ezwznasfl $711 (ff/1,

%z.'sATT0RNEY till atented den 5, 1926,

Application area @ctcher as,

To all whom it may concern:

Beit known that l, Enasnrus D. Strum, a citizen of the United States of America, residing at Rochester, in the county of Monroe and State of New York, have in vented certain new and useful Improvements in Generators, of which the following is a specification.

My invention relates to a generator, and has for its principal object to aftord a simple, practicable and ellicient mechanism which can be operated economically for the charging of storage batteries and other analogous uses.

A more particular purpose of the invention is to provide a direct current generator that will maintain a substantially constant voltage at its terminals, and which is elffectually protected against injury, in the event of failure of power from the motor that drives the generator, or a decrease in the generator voltage below that of the line to which it is connected.

A further object of m improvement is to automatically increase t e field strength ol the generator as the load on the generator increases, by a mechanism that positively prevents a reversal of the magnetism in the field, in the event of reversal of current in the main generator circuit.

Another purpose of the invention is to provide for increases in the generator field strength as the load increases, vvhile preventing decreasing the field strength hegond a predetermined fixed point, that is ut slightly below normal, so that no substantial decrease in field strength takes place it the generator should run as a motor supplied by current from the battery being charged, or other source.

Specifically, the invention has for its object to afi ord a magnetic toy-pass or diverting instrumentality extending itrom each pole iece partially around the armature and t ence toward the frame, and to control said by-pass from the main gen orator circuit in such a way as to vary the amount of leakage therethrough, causing more magnetism to pass through the armature as the load is increased, the lay-pass being constructed and arranged so as to cause the generator to operate at a safe speed when operating as a motor;

The invention is based upon the principles characterizing the mechanism that will he understood from the following description,

filo. (l itwtlil.

when read in conjunction with the ocean panying drawing, the novel features heing pointed out in the claims following the description.

in the drawing:

Figure l is a diagrammatic view illustrat ing one adaptation of the invention, and

Figure 2 is a perspective view of the pole piece and integral diverter pole.

lFhere are numerous ways in which the features of my improvement can he carried out, and for purpose of illustration one example of a practicahle mechanism, 1 have disclosed a direct current generator such used for a storage battery charging outfit.

ln the construction shown, 1 designates the armature which is rotated by a suitable motor, as well understood in the art, While 2 designates a stationary part of the held, 3 designating the pole pieces of the field supported on the frame 2, as usual in this class of structures. 4% the main generator circuit connecting itv brushes 5 to the armature and leading r batteries to be charged, While 6 are co nected with the main circuit and sail-. ing the pole pieces The generation of current dope the passing oi? magnetic lines or? e he tween the ole pieces 3 through the l, and l invention is based upon the discovery th 3 these magnetic lines ct force may be partially diverted around the armature instead of passing through it, and the extent or amount of such diversion of magnetism can be controlled automatically so as to in crease the magnetism passing through the armature as the load increases, and decrease it as the load decreases.

Une practicable and successful way of 1-6 coniplishing this result consists of a magnetic by-pass in the form of an extension 7', preferably formed of iron or steel, integral with each pole piece 3, and extending par tially around the armature, as shown l"he end of the extension Y projects outwardly towards the frame, preterabl to a point in close proximity thereto affording a diverter pole 8 around which is Wound a coil a in series with the main. circuit a, so that the generated current in the main circuit con tinuously passes through the coil 9 of each diverter pole.

Current travels normally through the cells 9 in such a direction as to oppose the f rce causing lealrage'through the diverter frame constituting its so that as the current increases, it causes a greater amountof magnetism to pass through the armature, and maintains a practically constant voltage at the terminals 5. Preferably, the diverter pole is so designed that the amount of magnetism diverted by 1t at no load is such that when redirected through the armature upon increased load, it will cause the generated voltage to equal the terminal voltage plus the internal voltage drop.

The cross section and arrangement of portion 7 oi the diverter pole is such that when the generator is operating normally withuo load, considerable magnetism is passing through the diverter pole and portion 7 is near its point of satin-ration. Therefore very little additional magnetism need be diverted to bring to complete saturation, after which the divcrter pole will divert substantiaily no additional magnetism from its path to the armature. The amount of magnetism passing through portions 8 of the divcrter poles can be very considerably reduced, however, in order to strengthen the main field upon increasing load conditions, and the reasons for these conditions will now be explained. c

If the generator speed is decreased, owing to a change in speed or entirefailure of the motor which drives the generator, the generator voltage drops proportionately, and this drop is sometimes such as to result in the generator voltage being lower than that of the battery being charged, whereupon the latter drives the generator as a motor.

-Under these conditions, the current in the main generator circuit is reversed, and it is essential that this shall not have the effect of substantially weakening the magnetism in the main field to the point of permitting the armature to turn at an excessive speed. With the construction described above, the diverter pole prevents the main magnetic. field strength from being substantially decreased when the main current reverses. since portion 7 quickly reaches a point of complete saturation, alter which practically no "further leakage occurs. irrespective of the amount of current in the diverter pole coil.

Under these conditions. the main magnetic field strength is held at such a point as to cause the generator to run as a motor without excessive speed and without doing any injury. As soon as the generator driving motor resumes operations. or returns to normal speed, the generator voltage increases to a point above that of the battery, and again functions normally. While charging, a practically constant voltage at the generator terminals is assured, because as the generated current increases, the amount of magnetism passing through portion 8 or the diverter poles is d creased. and that pass ing to the armature correspondingly in- Memes creased, so that the field strength is increased proportionately to an increase of current in the main generator circuit.

While I have described the invention with reference particularly to a certain structural embodiment. it is not confined to battery charging or to any of the details shown, and my improvements may be practicably adopted in other modified arrangements Without departing from the principles of the improvements, or the scope of the following claims.

I claim:

1. A generator comprising a field including a frame and pole pieces, an armature, diverting means arranged to divert magnetism from the pole pieces around the armature instead of through it, and means acting automatically to vary the amountof magnetism so diverted in accordance with changes in the amount of generated current, said diverting means being so constructed that there is no substantial increase in diverted magnetism and no substantial decrease in the main field strength upon reversal oi current when the generator acts as a motor, whereby the generator may safely operate as a motor without excessive speed.

2. A generator comprising a field including a frame and pole pieces, an armature, diverting means arranged to divert magnetism from the pole pieces around the armature instead of through it, and currentcontrolled means acting to vary the amount of magnetism so diverted, said diverting means being so constructed that there is no substantial increase in diverted magnetism and no substantial decrease in the main field strength upon reversal of current when the generator acts as a motor, whereby the generator may safely operate as a motor without excessive speed.

3. A generator comprising a field including a. frame and pole pieces, an armature, diverting means arranged to divert magnetism from the pole pieces around the armature instead of through it, and a main circuit cooperating directly with said diverting means and acting to vary its reluctance in accordance with changes in the amount of generated current, said diverting means hein so constructed that there is no substantifi increase in diverted ma netism and no substantial decrease in the main field strength upon reversal of current when the generator acts as a motor, whereby the generator may safely operate as a motor without excessive speed.

4. A generator comprising magnetism divertingmeans controlled by the generated current for increasing the field strength proportionately to the increase in current. and preventing substantial reduction in the magnetism in the main field upon reversal of current'in the main line whereby the generator may operate as a motor without excessive speed.

5. A generator comprising a field including a frame and pole pieces an armature, a ma etic by-pass exten ing partially aroumf the armature from the inner end of each pole iece to a spaced oint on the frame, an current controll means for varying the reluctance of said b ass.

6. A generator comprising a e d including a frame and pole pieces, an armature, a ma etic by-pass extending partially armin the armature from the inner end of each pole piece to a spaced point on the frame, and current controlled means aetin upon said by-pass to increase the main fielg strength pro ortionately to an increase in current, sai by-pass being magnetically saturated whereby a substantial decrease in the main field strength is prevented upon reversal of current in the main line.

7. A generator comprising a field including a frame and pole pieces, an armature, a magnetic by-pass extending partially around the armature from the inner end of each pole piece to a spaced point on the frame, and current controlled means acting upon said by-pass to increase the main field strength proportionately to an increase in current, said b ass having a restricted section so locatecl 5181 said current controlled means acts to redivert the leakage magnetism across the air p to the armature but will not substantial y reduce the magnetism in said main field upon reversal of current in said current controlled means.

8. A generator comprising a field including a frame and pole piece, an armature, a diverter pole connected with said pole piece and extending partially around the armature and thence towards the frame, and current controlled means for varying the reluctance of said diverter pole.

9. A generator comprising a field including a frame and pole piece, an armature, a diverter pole connected with said pole piece and extending partiall around the armature and thence towards t e frame, a main cirsuit, and a coil surrounding said diverter pole and connected in series with the main circuit.

10. A generator comprising a field including a frame and p0 e pieces, an armature, a diverter pole formed integralwith each ole piece and projecting partially around the armature and thence towards the frame, a main circuit, and a coil in series with said main circuit and surrounding each diverter pole.

In witness wherwf, I have hereunto signed my name.

D. SMITH. 

